Abstract: Porcelain mortars and pestles are frequently used to comminute
drug substances on a small scale and (in some cases) in the production
of liquid and semisolid suspensions. Although it is generally
accepted that removal of a drug substance from a rough
surface by rinsing may be difficult and may lead to cross-contamination,
no hard data support that theory. In this study, the
amount of salicylic acid remaining on a porcelain mortar after
different washing procedures was quantified and compared with
the amount remaining on a plastic mortar. Drug residues in the
“mg” range on the porcelain mortars made common rinsing procedures
appear inappropriate, but no traces of drug were detected
on plastic mortars. In addition, the quality of suspension
ointments with respect to particle size and homogeneity
produced by the two types of mortars was compared. Porcelain
and plastic mortars appeared equally suitable for use in the
production of semisolid suspensions.